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a, PT: \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
b, Ta có: \(n_{O_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
Theo PT: \(n_{Fe_3O_4}=\dfrac{1}{2}n_{O_2}=0,1\left(mol\right)\)
\(\Rightarrow m_{Fe_3O_4}=0,1.232=23,2\left(g\right)\)
c, PT: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
Có: O2 hao hụt 40% → H% = 100 - 40 = 60%
Theo PT: \(n_{KMnO_4}=2n_{O_2}=0,4\left(mol\right)\)
\(\Rightarrow n_{KMnO_4\left(TT\right)}=\dfrac{0,4}{60\%}=\dfrac{2}{3}\left(mol\right)\)
\(\Rightarrow m_{KMnO_4}=\dfrac{2}{3}.158\approx105,3\left(g\right)\)
a,4P+5O2→t02P2O5
b,nP=mM=6,232=0,19375(mol)
Theo PTHH :
nO2=54nP=54.0,19375=0,24(mol)
⇒VO2=n.22,4=0,24.22,4=5,376(l)
c, Theo PTHH :
nP2O5=12nP=12.0,19375=0,097(mol)
⇒mP2O5=n.M=0,097.142=13,774(g)
d, 2KMnO4→K2MnO4+MnO2+O2
Theo PTHH :
nKMnO4=2nO2=2.0,24=0,48(mol)
⇒mKMnO4=n.M=0,48.158=75,84(g)
a,\(4P+5O_2\rightarrow^{t^0}2P_2O_5\)
\(b,n_P=\dfrac{m}{M}=\dfrac{6,2}{32}=0,19375\left(mol\right)\)
Theo PTHH :
\(n_{O_2}=\dfrac{5}{4}n_P=\dfrac{5}{4}.0,19375=0,24\left(mol\right)\)
\(\Rightarrow V_{O_2}=n.22,4=0,24.22,4=5,376\left(l\right)\)
c, Theo PTHH :
\(n_{P_2O_5}=\dfrac{1}{2}n_P=\dfrac{1}{2}.0,19375=0,097\left(mol\right)\)
\(\Rightarrow m_{P_2O_5}=n.M=0,097.142=13,774\left(g\right)\)
d, \(2KMnO_4\rightarrow K_2MnO_4+MnO_2+O_2\)
Theo PTHH :
\(n_{KMnO_4}=2n_{O_2}=2.0,24=0,48\left(mol\right)\)
\(\Rightarrow m_{KMnO_4}=n.M=0,48.158=75,84\left(g\right)\)
a) PTHH: 4Al + 3O2 =(nhiệt)=> 2Al2O3
nAl = \(\frac{5,4}{27}=0,2\left(mol\right)\)
b) nO2 = \(\frac{0,2\times3}{4}=0,15\left(mol\right)\)
=> VO2(đktc) = 0,15 x 22,4 = 3,36 lít
c) nAl2O3 = \(\frac{0,2\times2}{4}=0,1\left(mol\right)\)
=> mAl2O3 = 0,1 x 102 = 10,2 gam
a. \(n_P=\frac{6,2}{31}=0,2mol\)
\(V_{O_2}=V_{kk}.\frac{1}{5}=\frac{18,48}{5}=3,696l\)
\(n_{O_2}=\frac{3,696}{22,4}=0,165mol\)
PTHH: \(4P+5O_2\xrightarrow{t^o}2P_2O_5\)
Tỷ lệ \(\frac{0,2}{4}>\frac{0,165}{5}\)
Vậy P dư
\(n_{P\left(\text{phản ứng }\right)}=\frac{4}{5}n_{O_2}=0,132mol\)
\(n_{P\left(dư\right)}=0,2-0,132=0,068mol\)
\(\rightarrow m_{P\left(dư\right)}=0,068.31=2,108g\)
b. \(n_{P_2O_5}=\frac{2}{5}n_{O_2}=0,066mol\)
\(\rightarrow m_{P_2O_5}=0,066.142=9,372g\)
c. PTHH: \(2KClO_3\xrightarrow{t^o}2KCl+3O_2\)
\(n_{KClO_3}=\frac{2}{3}n_{O_2}=0,11mol\)
\(\rightarrow m_{KClO_3}=0,11.122,5=13,475g\)
\(n_{O_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)
a. PTHH: \(4P+5O_2-t^o->2P_2O_5\left(1\right)\)
b. Theo PT (1) ta có: \(n_{P_2O_5}=\dfrac{0,05.2}{5}=0,02\left(mol\right)\)
\(\Rightarrow m_{P_2O_5}=0,02.142=2,84\left(g\right)\)
c. PTHH: \(2KMnO_4-t^o->K_2MnO_4+MnO_2+O_2\uparrow\left(2\right)\)
Ta có: \(n_{O_2}=0,05\left(mol\right)\)
Theo PT (2) ta có: \(n_{KMnO_4}=\dfrac{0,05.2}{1}=0,1\left(mol\right)\)
\(\Rightarrow m_{KMnO_4}=0,1.158=15,8\left(g\right)\)
\(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
\(nO_2=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
\(\Rightarrow nP_2O_5=\dfrac{2}{5}nO_2=\dfrac{2}{5}.0,1=0,04\left(mol\right)\)
\(\Rightarrow mP_2O_5=0,04.\left(31.2+16.5\right)=5,68\left(g\right)\)
c/
pthh: \(2KMnO_4\rightarrow K_2MnO_4+MnO_2+O_2\uparrow\)
\(nO_2=0,1\left(mol\right)\)
\(\Rightarrow nKMnO_4=\dfrac{2}{1}.nO_2=\dfrac{2}{1}.0,1=0,2\left(mol\right)\)
\(\Rightarrow mKMnO_4=0,2.\left(39+55+16.4\right)=31,6\left(g\right)\)
1) nFe3O4= 46,4:232=0,2 mol
PTHH :3Fe+2O2\(\rightarrow\) Fe3O4
0,6 0,4 \(\leftarrow\)0,2 (mol)
PTHH: 2KMnO4\(\rightarrow\) K2MnO4+MnO2+O2
0,8 \(\leftarrow\) 0,4 (mol)
\(\Rightarrow\) m KMnO4= 0,8.158=126,4 g
1) 3Fe + 2O2 ---> Fe3O4 ---> nO2 = 2nFe3O4 = 2.46,4/232 = 0,4 mol.
2KMnO4 ---> K2MnO4 + MnO2 + O2 ---> nKMnO4 = 2nO2 = 0,8 mol
---> mKMnO4 = 158.0,8 = 126,4 g.
2) KClO3 ---> KCl + 3/2O2 ---> nKClO3 = 2/3nO2
---> nKClO3:nKMnO4 = 2/3:2 = 1:3 ---> mKClO3:mKMnO4 = 158/3.122,5 = 0,43
3) KNO3 ---> KNO2 + 1/2O2 ; Cu(NO3)2 ---> CuO + 2NO2 + 1/2O2
Như vậy nếu thu được cùng lượng oxi thì KClO3 sẽ có khối lượng nhỏ nhất.
1.
\(2KClO_3\underrightarrow{^{to}}2KCl+3O_2\)
\(n_{KClO3}=\frac{9,8}{122,5}=0,08\left(mol\right)\)
\(\Rightarrow n_{O2}=\frac{3}{2}n_{KClO3}=\frac{3}{2}.0,08=0,12\left(mol\right)\)
\(\Rightarrow V_{O2}=0,12.22,4=2,688\left(l\right)\)
2.
\(a,2KMnO_4\underrightarrow{^{to}}K_2MnO_4+MnO_2+O_2\)
\(b,n_{O2}=\frac{33,6}{22,4}=1,5\left(mol\right)\)
\(\Rightarrow n_{KMnO4}=2n_{O2}=2.1,5=3\left(mol\right)\)
\(\Rightarrow m_{KMnO4}=3.158=474\left(g\right)\)
3.
\(2KMnO_4\underrightarrow{^{to}}K_2MnO_4+MnO_2+O_2\)
1____________________________0,5
\(2KClO_3\underrightarrow{^{to}}2KCl+3O_2\left(1\right)\)
1____________________1,5
Đặt \(n_{KMnO4}=n_{KClO3}=1\left(mol\right)\)
\(V_{O2\left(1\right)}=0,5.22,4=11,2\left(l\right)\)
\(V_{O2\left(2\right)}=1,5.22,4=33,6\left(l\right)\)
Vậy nung KClO3 sẽ cho thể tích oxi nhiều hơn.
Số mol oxi đã dùng ở dktc là: nO2=3,36\22.4=0,15 (mol)
PTHH: 5O2+4P−dđiều kiện nhiệt độ−>2P2O5
Từ PTHH => nP2O5=2\5nO2=0,06.(mol)
Khối lượng P2O5 thu được sau phản ứng là:
mp2O5=0,06.142=8,52(g)
PTHH:
2KMnO4−dđiều kiện nhiệt độ−>K2MnO4+MnO2+O2
Từ PTHH => nKMnO4=2nO2=0,3(mol)
Khối lượng KMnO4 cần dùng là:
mKMnO4=0,3.158=47,4(g)
a, \(4P+5O_2\underrightarrow{^{to}}2P_2O_5\)
b, \(n_{O2}=\frac{3,36}{22,4}=0,15\left(mol\right)\)
\(n_{P2O5}=\frac{2}{5}n_{O2}=0,06\left(mol\right)\)
\(\rightarrow m_{P2O5}=0,06.142=8,52\left(g\right)\)
c, \(KMnO_4\underrightarrow{^{to}}K_2MnO_4+MnO_2+O_2\)
\(m_{KMnO4}=2n_{O2}=0,12\left(mol\right)\)
\(\rightarrow m_{KMnO4}=0,12.158=18,96\left(g\right)\)